1. Field of the Invention
This invention relates to a laminate film for protecting printed images and imparting gloss to printed images. More particularly, the present invention relates to a laminate film for bringing an image formed by an ink-jet recording system using dye type ink materials into a state of being effectively kept out of external active gases (ozone gas, etc.) to improve the fading property of the image and an image protection method using the same.
2. Related Background Art
Ink-jet recording systems are known as a method of outputting photographs in place of silver halide photography. The initial image quality of images produced by the ink-jet recording system is comparable with that of photographs. However, in terms of preservability of image, it has been difficult to prevent image deterioration caused with the lapse of time. Specific problems that have to be dissolved for preserving images include that the UV resistance, the gas resistance and the water resistance of images have to be improved. Particularly, in the case of photographic images, the gas resistance of images desirably has to be improved because a poor gas resistance can be problematic in practical applications.
In the case of recorded images produced by ink-jet recording systems, the gas resistance of dyes in ink varies depending on the structure of an ink receiving layer of a recording medium where the image is recorded. The ink receiving layer of a swelling type recording medium swells to contain the dyes of the ink therein at the time of ink-jet recording so that the dyes can hardly fade. On the other hand, in the case of a void type recording medium dyes used for forming an image are attacked by active gases that penetrate through voids in the recording medium so that they are liable to fade.
However, from the viewpoint of high-speed printing, swelling type recording mediums are not suited for high speed printing because they poorly absorb ink. To the contrary, void type recording mediums are good for high speed printing because they have voids and hence they absorb ink excellently. While it may be conceivable to use pigment type ink in place of dye inks in order to avoid the problem of fading, pigment inks are accompanied by problems in terms of coloring effect.
Techniques for protecting an image by laminating an image formed surface of a recording medium after forming the image on it by means of an ink-jet recording system are known to improve the light resistance of the image when it is left outdoors and exposed to light for a long time (see Japanese Patent Application Laid-Open Nos. H7-156568, H8-224838 and H8-258210).
On the other hand, laminate films formed by arranging a peelable layer, a functional layer and a coating layer on a substrate are known (see Japanese Patent Application Laid-Open No. H11-348437).
However, when the image formed surface of a recording medium is laminated by a laminate film described in any of the techniques described in the above cited patent documents, pin holes can be produced on the image formed surface and active gases penetrate through the pin holes to fade the image. Additionally, when laminating an image formed surface of a recording medium where an image is printed without margins like a silver halide photograph, active gases can penetrate through the lateral edges of the recording medium to fade the image along the four sides (edges) thereof.